This is the American classification. 1.Complete injury Sacral segment S4.5 without any preserved motor and sensory function 2.Incomplete injury Below the nerve plane, including sacral segment S45, there is sensory function, but without any motor function 3.Incomplete injury Below the nerve plane there is preserved motor function, more than half of the key muscles muscle strength ∠3 level 4.Incomplete injury Below the nerve plane there is preserved motor function, more than half of the key muscles muscle strength ≥ 3 level 5.Normal Sensory and motor functions are normal